The `withInitialConversation` method is used to enable loading of conversation history before
rendering the `AiChat` component. This is useful if you want the user to resume a conversation
from a previous session.

* Types: `initialConversation: ConversationItem[]`

With `ConversationItem` being defined as:

```ts
type ParticipantRole = 'user' | 'system' | 'ai';
type ConversationItem = {
    role: ParticipantRole;
    message: string;
}
```

* Optional
* Usage:

```javascript
const aiChat = createAiChat()
    .withInitialConversation([
        {
            role: 'user',
            message: 'Hello AI chatbot! What\'s the capital of Antartica?'
        },
        {
            role: 'ai',
            message: 'Antarctica, the cool place where penguins rule, doesn\'t have a capital because it\'s too chill for politics!'
        }
    ]);
```
